STC Rebate Calculator Australia 2026
Work out your federal Small-scale Technology Certificate (STC) rebate — the upfront discount on solar (and now batteries) — plus feed-in tariff income, payback and lifetime savings. The rebate shrinks every year until the scheme ends in 2030, so timing matters.
1 Your system
6.6 kW is the most common Australian residential size (paired with a 5 kW inverter).
Zones are set by the Clean Energy Regulator's postcode map; sunnier zones earn more certificates per kW.
Deeming period 2026: 4 years remaining to 2030. It drops by one each January — install sooner for a bigger rebate.
STCs trade at roughly $35–$40; the regulated ceiling is $40. Installers usually apply this as an instant point-of-sale discount.
2 Battery — optional
3 Cost & savings
Australian residential solar is among the cheapest in the world — roughly $0.90–$1.40 per watt before the STC discount.
Feed-in tariffs are set by retailers and are low (often 3–8c), so self-consumption is worth far more than exporting.
Without a battery, homes typically self-consume 30–50%. A battery pushes this to 70–85%.
Most of Australia gets ~3.8–4.6 kWh per kW per day; the sunnier north is higher.
Indicative estimates only. STC value, zone factors and deeming period are set by the Clean Energy Regulator and change over time; feed-in tariffs vary by retailer and state. Confirm current figures and get installer quotes before purchasing.
How the STC rebate is calculated
system size (kW) × zone rating × deeming years (rounded down).Zone ratings: Zone 1 = 1.622, Zone 2 = 1.536, Zone 3 = 1.382, Zone 4 = 1.185.
Deeming years = whole years from install to 31 Dec 2030 (4 in 2026, 3 in 2027, 2 in 2028, 1 in 2029).
Rebate =
STCs × STC price (≈$35–$40 each), applied as an upfront discount.Battery STCs are tiered on usable capacity: 100% of the factor on the first 14 kWh, 60% on 14–28 kWh, 15% on 28–50 kWh, with the per-kWh factor (6.8 from May 2026) declining over time.
Savings = self-consumed solar × your rate + exported solar × feed-in tariff. Source: Clean Energy Regulator (cer.gov.au) — verify current values before purchasing.
Solar in Australia: the STC rebate explained
Australia has one of the world's highest rates of rooftop solar adoption, and a big reason is the federal STC scheme, which knocks a substantial discount off the upfront cost of a system. Combined with abundant sunshine, high electricity prices and feed-in tariffs for exported power, solar pays back quickly for most Australian homes. This calculator estimates your STC discount, feed-in income and payback, using the scheme's mechanics — though the precise STC value floats with the market, so treat figures as dated references.
What STCs are and how they discount your system
Small-scale Technology Certificates (STCs) are created when you install an eligible solar system, under the federal Small-scale Renewable Energy Scheme. Each certificate represents roughly a megawatt-hour of expected clean generation, and your system earns a number of them based on its size, your location's solar zone, and the years remaining until the scheme ends in 2030. In practice you assign the STCs to your installer, who discounts them off your price upfront — so you rarely handle certificates directly; you just see a lower quoted cost. The dollar value depends on the STC market price, which fluctuates, so the discount varies somewhat over time.
Why the rebate shrinks every year
An important, honest point: the STC incentive declines annually. Because certificates are based on the years of generation remaining until the scheme's 2030 end date, a system installed this year earns fewer certificates than the same system installed last year, and more than one installed next year. This creates a genuine (rather than manufactured) reason the upfront discount falls over time — it's built into the scheme's design. It's worth understanding, but not a cause for panic-buying: the shrinking rebate is gradual, and falling system prices have historically offset much of the decline.
Feed-in tariffs and self-consumption
On top of the upfront STC discount, you earn a feed-in tariff for electricity you export to the grid. As in most markets, though, feed-in rates have fallen well below retail electricity prices, so — as elsewhere — self-consumption is now where the real savings lie. Using your solar as it's generated avoids buying grid power at the full rate, while exporting earns only the modest feed-in tariff. Shifting usage into daylight hours, or adding a battery, increasingly drives Australian solar returns, just as it does in the UK, California and elsewhere. The calculator separates self-consumption from export so your estimate reflects this.
Batteries and state programs
With feed-in tariffs low and electricity prices high, home batteries have become increasingly popular in Australia, and various state-level battery incentives have come and gone over time. Whether a battery pays depends on your usage pattern, your feed-in rate and any current state support — the same spread logic that governs storage everywhere. Check for state programs in your area, as they can materially change the battery case, and weigh storage against how much grid power it actually displaces for you.
Frequently asked questions
It's the discount from Small-scale Technology Certificates under the federal Small-scale Renewable Energy Scheme. Your system earns certificates based on its size, your solar zone and the years to 2030; you assign them to your installer, who takes their value off your upfront price.
Because certificates are calculated on the generation years remaining until the scheme ends in 2030. Each year there are fewer years left, so a system earns fewer certificates and a smaller discount. It's a built-in, gradual decline — not a sudden cut-off — and falling system prices have offset much of it historically.
Very much so for most homes — high sunshine, high electricity prices, the STC upfront discount and feed-in income combine for fast payback. As feed-in rates have fallen, self-consumption (and increasingly batteries) drive the strongest returns. Run your figures through the calculator for an estimate.
It depends on your usage, your feed-in rate and any current state battery incentive. With low feed-in tariffs and high grid prices, storing and using your own solar is increasingly valuable, but the battery's cost still has to be justified by how much grid power it displaces. Check for state programs that may improve the case.